BBC News Published image copyrightReuters/Instagram image captionAlexei Navalny was released from hospital in September after more than a month of treatment A joint investigation published on Monday has blamed Russian intelligence agents for the poisoning of top Russia opposition figure Alexei Navalny. In August Mr Navalny - a staunch critic of President Vladimir Putin - was poisoned with the nerve agent Novichok. He has accused Mr Putin of ordering the attack, something the Kremlin denies. But investigative journalists at Bellingcat and Russian news site The Insider have now published a report implicating FSB agents in the incident. According to the investigation - compiled with the help of US broadcaster CNN and German paper Der Spiegel - a group of operatives from the Russian state intelligence organisation tailed Mr Navalny for three years.